Electric switch



Dec. 9, 1941. A. L. JUDsoN 2,265,486

ELECTRIC SWITCH Filed May 31, 1959 5* 4 zei IIIIIIII lllllllll K Patented Dec. 9, 1941 ELECTRIC SWITCH l Albert L. Judson, Portland, Oreg., assignor to- L. R. Tceple Company, Portland, Oreg.

Application May 31, l193%), Serial No. 276,678

'z claims. (ci. zoo-ps1) This invention relates to improvements in electric switches especially adapted to be constructed as a self-contained unit of small dimension.

Objects of the invention are to incorporate in Y a switch employing magnetic snap-action, a resilient coupling between armature and contacts whereby contact pressure may be increased without increase in operating eiort; to incorporate in a switch of this character means for damping any tendency `lof the moving contact member to rebound; to incorporate in a switch, employing' a magnet and a resilient member between armature and switch operator to effect snap-action, adjustable means for varying the spring rate ofthe resilient member.

The foregoing and other objects will appear as my invention is more fully hereinafter described in the followingspecication, illustrated in the accompanying drawing, and finally pointed out in the appended claims.

. 'In the drawing: v

Figure l represents a view in perspective of the entire switch as assembled for application. 1

4Figure 2 represents a View in perspective of the entire switch revealing the terminals or binding posts.

Figure 3 represents a view in perspective of the switch with the cover removed to show the relationship of the working parts.

Figure 4 represents a view of a longitudinal vertijcal section, taken on the line 4-4 of Figure Figure 5 is a sectional view taken on the line F545 of Figure 4.

Figure 6 represents a view of a section taken on the line 6-6 of Figure 4.

Figure 7 represents a view in perspective of one of the'members of the switch mechanism.

Figure represents a view of an enlarged T-he essence of this invention resides in;the

' against a. suitable standard 3|.

veniently vformed upon the standard 3| may bev means employed to produce certain novel effects depending upon a unique resolution of spring potentials transmitted through a system of aprigidly mounted at iltted with a suitable contact point 5. Attached to the'other side of the spring lmember 3 is a vertical extension Iiin rigid relationship. A frame 31 is secured to the base 22 and supports the operative members. A switch arm 1 is pivotally supported at.8 and is formed 'in detail with an extruded portion 9 to form a tongue Ill thereunder which normally extends through an aperture 34 in vertical extension 6 of the member 3. A leaf spring II of relatively small size is rigidly attached at one end of the switph arm l 'trated in detail by Figure 7,' and at I2. The other end of this spring Il extends to a position I3 above the said vertical exten-l sion 6 upon whichit'constantly bears with comparatively light pressure when the switch is open and a greater pressure when the switch is closed.

`On the opposite side of the pivot 8 `is an extension of the switch arm I formed with a bearv inlg'surface I4.

-A lever I5 is pivotally supported at I6 and is formed at one extremity with a' depending portion ll, in bearing upon said bearing surface. Il, and upon the opposite side of the pivot I6 with an extension I8 into which the screw I9 'is tapped. dlustably secured by the screw I9.

to the lever I5 are a sliding support 2U, illusa second leaf spring 2l.

The whole of this mechanism is suitable base, 22 preferably of folded dielectric material and is enclosed by a suitablecover 23 removably` attached to the base 22 by the screws 2t and 25 in a conventional manner.

.A plunger 26 extends through a suitable perforation and bearing in the cover`23 formed within the boss 2l and is formed upon its lower extremity with a suitable head 28 adapted to bear upon the free end of the spring 2 l.

The switch arm l is made of a ferrous or magnetic metal and is urged w that limit of its oscillatory movement about the pivot 8 at whichthe same is shown in Figure 4, by a permanent magnet 29 adjustably supported by means of the screw 30 serving to compress the magnet 29 A stop 32 conbent to such a position as will provide the proper spacing and relationship between the switch-arm l and permanent magnet 29'.

The devic'e is so adjusted that the contact point Sengages the contact 'pointu4 at some instant prior to the contact of theswitch arm 'I 'with the stop 32, providing a deilectionof the spring Il one end indicated at 4 and secured to a L beyond that at which the contact of the points 5 and 33 is electrically perfected.

The contact points 5 and 33 are normally held in forcible contact by the pre-strained 'spring member 3 supplemented by the pressure exerted by the spring upon the vertical extension 6. The energy required to disengage contacts 5 and 33 is suppliedthrough plunger 26 usually actuated in relatively slow motion. Slow movement of the plunger 26 is transformed into potential energy by deflectionv of the spring 2| and is accumulated therein until a force is invested suflicient to overcome the said magnetic attraction of the arm 'I by the magnet 29. It naturally follows that when this magnetic attraction has been overcome, the latter will diminish in intensity at a more rapid rate than that at which the force of the `spring 2| is attenuated in its movement to the unstrained form.

Since the levers l5, I4 and l are necessarily rigid structures and, therefore, of appreciably ponderable mass, the celerity of movement thereof consequent upon the application of a given force will be relatively more sluggish than` that celerity with which the relatively light parts will move in response to the same force.

An element of time, therefore, during which the switch arm I and the lever I5 may be accelerated to a maximum velocity before electrical contact between the points 5' and 33 is broken, is provided. for by an appreciable amplitude of free movement a of the switch varm 1 before the tongue I thereof engages the extension 6 at the upper extremity of the aperture 34 to disengage the contacts and 33.

Prior to the instant of actual engagement of the switch-armi with the element s as just described, the switch arm 1l is motivated at an accelerated velocity by means of three coacting effects.

The resistance to upward movement of the switch-arm 1 oiered by the magnet 29 is of rapidly attenuated value. The force of the spring 2| is of relatively more slowly attenuated value so that the effective force thereof actuating the switch-arm 'l is of increasing magnitude. Thirdly, the spring acting to hold thecontacts 33 and 5 in engagement with a force supplementing the normal force of the spring member 3, reacts with a supplementary force to accelerate the upward movement of the switch-arm 'I at a rapid rate.

Thus the switch-arm 1 in rapidly accelerated motion operates to disengage the contacts 33 and 5 at such a speed as to eliminate destructive arcing effects.

Another effect which serves to damp out undesirable vibrations of the contact point 5 and the spring 3 upon contact closure results from the relatively dissimilar natural rates of vibration Yvarious mechanical equivalents for these ele` tude of the movement of the plunger 26 may be reected in commensurate and inverse alteration of the force.

Provision for this adjustment of the stroke of the plunger 26 is provided for by the adjustable spring support 20 which may be extended or retracted longitudinally in contact with the fixed end of the spring 2|, to vary the effective length, and resilience of the latter.

It to be observed that from this novel combination of properties as embodied in the apparatus described, an improved switch of the type is supplied. It is to be especially noticed'that ments may be readily substituted Without evasion of the. invention itself. For example, the spring 2| may be omitted without altering the identity of the combination \of properties considered to be the invention in the above described combination of elements, but such omission of the spring 2| removes from the switch proper abrupt orl snap-acting functions thereof described. Without the spring 2|, however, the switch would be operative in a practical sense inasmuch as resilience may be provided in the linkage between prime mover-and plunger, or incorporated in the prime mover itself. Furthermore the spring though it imparts desirable features, is not essential to the basic structure of the switch and of the springs 3 and and the parts attached 1 quantity and that any adjustments of the ampli- 75 may therefore be omitted when certain considerations indicate such omission desirable.

Similarly, various mechanical equivalents for the spring may be substituted without altering the identity of the combination of properties considered to be the invention, as, for example, the equivalent shown in Figure 10.

In Figure 9 is shown a switch of variant form in which thel elastic element represented by the spring 2|' in the switch as described hasbeen disposed externally to effect an economy of dielectric material yand conserve space. In this form the plunger 26 is interposed between the externally disposed lever lI5' and the bearing corresponding to I4. The operating characteristics, however, are identical with those of the switch described.

In Figure 10 another form of the device embodying the elements of this invention is illustrated, the same being the mechanical equivalent of the device, as represeted in' Figure 8. In this figure, corresponding parts are represented by' parts indicated by similar numerals with prime exponents. In this figure, the functions of the y of which, the spring may move to provide` the distance av through which a switch arm 'I' though continuously engaged by spring with the piece 6 and hence the contact point 5 may move without effecting motion of the contact point 5'. The vertical portion of arm |"which embraces space 34 is closely disposed with respect to extension 6 to effect a substantially rigid coupling after spring has deflected through distance a. Spring extends through a narrow slot in 6' which permits longitudinal but not vertical relative motion.

What I claim is:

f1. An electric switch Ycomprising an elasticl member tted with a contact point at one end and rigidly supported at the other end, a second contact point complementary to the contact point on said elastic member, two binding posts conductively-associated with said contact points, a switch arm pivotally mounted at one end, a permanent magnet disposed in apposition with the free end of said switch arm, a delayed action engagement connecting said switch arm to said elastic member and yieldingly operable means to actuate the said switch arm, said operable means including a resilient member convergent with and attached to a pivoted cam level` bearing upon said switch arm and adjustable spring damping means for rendering said resilient member rigid to a selected degree.

2. A pair of contact-points supported in apposition by means of dielectric and resilient means, a magnet. an oscillatory member of magnetic metal disposed in the eld of said magnet, resilient coupling means between said oscillatory member and said contact points, including means lto effect a slack motion engagement therbetween supplemented by a follower spring biased therebetween, and spring connections through which energy is transmitted to move said oscillatory member in opposition to the attraction of said magnet therefor.

3. Av pair of contact points supported and constrained together by means of dielectric and resilient means, a magnet, an oscillatory member of magnetic metal disposed in the field of said magnet', delayed-action connections mutually constraining said oscillatory member and said contact points to sequential motion to interrupt a current through the latter, an operator acting upon said oscillatoryv member in opposition to said magnet, and a follower spring carried by said oscillatory member and continuously engaging said resilient means adjacent the contact points supported thereby, said spring exerting a bias therebetween serving to spring-load said delayed-action connection to dampen out vibration and augment the tension of said resilient means. l

4. In a switch including a magnetic detent and a resilient member adapted for the storage o potential energy imparted by selected external operating means in opposition to said detent, adjusting means associated with said resilient member adapted to compensate said' member for the degree of resilience of the particular operating means selected, said adjusting means comprising an adjustable member adapted to impart a selected degree of rigidity to said resilu lent member by contacting a greater or lesser portion thereof.

5. In a switch in which a magnetic force is opposed by force transmitted through resilient means to effect abrupt separation of contact points normally constrained together, the combination of an oscillatory member acted upon by both said magnetic force and said resilient means and loosely coupled with and. thereby adapted to open one of said contact points, spring means supporting and biasing said one of said contacts independently of said member, and additional spring means transmitting the effecct of the magnetic force on said oscillatory member to the contact points when in closed position to enhance contact pressure, said additional spring means interposed across said loose coupling and biasing said coupling to a lesser degree when in contact-open position and to a greater degree when when in contact-closed position.

6. Ina switch employing a switch-arm for moving a separately supported and biased contact subsequent to initial contact-opening movement of said switch arm, the combination of a resilient mounting for `said contact point and a resilient member coupling said arm andl said contact mounting yieldingly prior lto and rigidly subsequent to such initial movement to open said contact, said resilient member transmitting pressure from said switch arm tothe contact when in contact-closed position to augment the bias of said resilient mounting.

in. a switch a pair oi contact points at= tached respectively to a base and to a spring arm supported by the base, and normally constrained together by said spring arm, means to open sai-d contacts abruptly including an amature ma,m netically restrained and coupled with said spring arm loosely when in contact-closed position and a resilientv actuator acting upon said amature in opposition to the magnetic restraint to eect separation of said contacts by said amature through said coupiing, and means for augment-7 ing the constraint between said contact points when in closed position including a spring inter1 posed between said armature and said. spring arm and exerting a. bias therebetween. of lesser magnitude when in contactopen position and of a greater magnitude when in contact-closed position.

, ALBERT L.7 JUDSON. 

